网页Sharks are a group of elasmobranch fish characterized by a cartilaginous skeleton, five to seven gill slits on the sides of the head, and pectoral fins that are not fused to the head. Modern sharks are classified within the clade Selachimorpha[1] (or Selachii) and are the sister group to the Batoidea (rays and kin).
网页Learn about different shark orders, including sawsharks, dogfish sharks, and angel sharks. Find facts and photos of various shark species, such as cookiecutter shark, lanternshark, and gulper shark.